Any an all advice is appreciated!

[dnarby]

OK, if I check the wiring against this:

http://www.gearhead-efi.com/Fuel-Inj...ull=1#post6957

and it matches, then I will have most likely verified I have an 16147060 PCM, correct?

[Six_Shooter]

It's already verified that you have a '7060 PCM. That's the ONLY PCM that GM ever produced with brown plugs, in that configuration.

[dnarby]

Roger that, tomorrow I'm going to trace wires according that diagram and see if anything is amiss.

Any suggestions?

Thanks in advance.

[dnarby]

I inverted the colors so I can print them out and more easily make notes on them. This might help someone else, so I'm putting them here (I don't want to put them in the main ECM/PCM diagram section as I'm new here and don't want to mess with someone else's kitchen).

Attachment 10563Attachment 10564Attachment 10565Attachment 10566Attachment 10567

[dnarby]

OK, so it looks like the previous owner punked this TBI setup pretty well.

I'm going to have to go through the whole thing, pin by pin and verify each connection is correct and possibly wire each one up again.

For instance, if I'm reading it correct, C1 is supposed to be fed 12v via an a 10A fused ignition wire. Right now it goes NOWHERE.

I'm probably going to need some real basic wiring advice here. I'm basically starting from scratch.

[Six_Shooter]

Yes, C1 is the ignition input, and without that the engine won't run.

[dnarby]

OK, I'm going through every single connection, and rewiring everything from scratch. Here's why, take a look at the existing wiring:

Attachment 10588


Attachment 10585

Attachment 10586

Attachment 10587

The original lunatic who wired this (and had it running) appears to have cut the fuse block out of the donor vehicle (allegedly a Chevy Silverado), wired everything into it with a lot of extra wires, and stuffed the whole thing into an old ammo box.

The wiring harness plug had a lot of black tar-like goo squirted into the ends of the connectors which was getting all over everything. It was a freakin' mess, so I took some notes, cut the whole thing away, and cleaned everything. I'm about 3/4 of the way through tracing all the connections, labeling them, and wiring them into the remaining portion of the fuse block, and making sure everything that's supposed to be fused has a the proper fuse. So far everything looks good (wiring harness seems OK, no shorts), there's only a few I haven't verified as good because they go back to the transmission and I'll have to jack the car up to check them.

Now, I need some hand-holding here, as I have never wired a vehicle before (I have a working knowledge of simple electrics/electronics, e.g. I know how to use a multimeter to check for continuity, resistance and voltage, what resistors, fuses and relays do, etc.).

There doesn't appear to be a relay to run the ignition system. It appears as though the ignition feed wire (last key position before CRANK), simply sends power to the fuse block which then passes current through the fuses to the ignition system (computer and coil). I've identified the fuel pump relay, and what looks to be either the fan relay or the headlamp relay, but no ignition system relay.

Obviously, I don't want to pass current through the switch directly if it's supposed to go through a relay as I'll probably need a fire extinguisher (if I'm lucky).

Is there supposed to be an ignition relay to power the ignition? Thanks in advance.

[Six_Shooter]

That black goo is a typical thing found on GM connectors. It's supposed to insulate the connectors from moisture.

Typically in GM vehicles up to the early to mid '00s (depending on the car line) the ignition switch fed the ignition circuits directly, so that's also a normal thing to see. However, it would be a good idea, especially on an older vehicle/retrofit to add a dedicated ignition relay. Last year as I was chasing a couple issues on my own car I added a relay for the injectors, another for the ignition, and one for the starter. My idle got smoother and it appeared the car pulled smoother and harder after adding the relays that were fed directly from the battery and controlled by the ignition switch.

[dnarby]

OK, the vehicle is a '92 (and the donor motor/TBI system is likely the same vintage) so then direct power from the ignition switch to the injectors/coil/ECM is not unusual, that's good to know.

I have a big bag of 30A relays, I'm guessing if the ignition switch had enough capacity to power the ignition circuits/injectors, a couple of 30A relays should be plenty to power the ignition circuits and the injectors.

Going out to check and rewire some more, many thanks for the help.

Once I get this running I'll reveal the vehicle, it should give any gearhead a chuckle (I'm chortling at getting this on the road myself).

[dnarby]

IT'S ALIVE!!!

Last wire to connect was the main coil feed, once I figured that out, it popped right off. Vroom-vroom! There's still a few wires left unidentified, but maybe they aren't necessary.

Lots left to do, still haven't road tested it yet to make sure it shifts OK, have to get it inspected (needs a windshield, which I have), probably needs the rotors turned, maybe a pad slap, need to verify the fan is working, check the rear diff lube, snug up the leaking transmission pan, rig up some sort of temp gauge, some bits of interior/exterior trim, etc. etc.

Plus I'll have to put a proper muffler on it, as right now it has a cherry bomb, and it's practically like straight pipes.

This is what the 350 lives in:
Attachment 10589

Yep, that's a Volvo 740 wagon, 1992 vintage.

I have a set of front and rear sway bars for it, so when I'm finished it will actually handle really well. I also have a set of over coil springs so when I'm done I'll be able to haul around 1000lbs in the back.

Not to mention it has a tow hitch. Since the drive train came out of a Silverado, I should (in theory) be able to tow 1000lbs more than one, because it weighs 1000lbs less than one!

I see a lot of ricers getting their fart cans blown off in the future.

Thanks for your help Six - identifying the ECM, having the schematics for it, and someone with experience willing to help gave me the confidence to tackle this.

[dnarby]

OK Six Shooter, I need a bit more help if you're willing... I'm trying to figure out how the coolant temperature sensor is supposed to be wired into the ECM, and how the fan control is supposed to work.

If push comes to shove, I can use the temperature switch in the Volvo radiator to trip a relay and run the fan. I don't see anything on the wiring schematic about running the fan relay though. Also, there's three heavy gauge wires going into the fan. Red to positive and green to negative run the fan in the proper direction. There's a third black wire though, and that ran back to the fan relay power. Any advice here?

Also, from what I've read, the ECM uses the temperature to control mixture so it's important for it to know what temperature the engine is at.

The coolant sensor seems to be between spark plugs 1 and 3. It has a single blade connector running into a wire that leads back to the general location of the ECM (currently not connected to anything).

I ran D3 to a common ground. D16 doesn't seem to come out anywhere, there's no unconnected yellow wire coming out of the harness. Can I splice the wire coming from the sensor into the wire going to D16?

Thanks in advance!

[Six_Shooter]

The '7060 does not control electric fans, so you will need to use other methods to control the electric fan. I do not know about your 3rd wire on the fan, might be dual speed, might be for some other reason.

The ECM needs it's own coolant temp sensor. This is generally located in the intake manifold near the thermostat housing, and is the best place for it from my experience. It will be a two pin sensor. The ground for the sensor is connected to the sensor ground (D3).

D3 does not go to a ground, it provides ground for sensors, to isolate noise sources from sensors and provide a known good signal reference. D16 should ONLY be connected to the CTS, so there should be no splicing, or tapping into any other wires.

[dnarby]

OK, thank you.

The fan is probably dual speed. I will read up on those.

EDIT: The CTS I'm looking at is evidently for the GAUGE, per https://www.youtube.com/watch?v=un2neiiNk8c

I'll get a chance on Friday to locate the the ECM CTS and attempt to hook it up correctly.

Also, I verified this thing does in fact have a limited slip rear. Just blipping the throttle barked both rear sneakers. Looking forward to having a fun car again (haven't had one in a long time).

Thanks in advance.

[dnarby]

Hi Six_Shooter,

Turns out I didn't ground D3 to a common ground (that was C8, I wrote that in error).

Did some more checking, located the actual ECT (it's to the left of the thermostat) and found that D3 and D16 when traced back to the ECM are *reversed*, that is the black wire from the sensor leads to the yellow wire at the ECM plug, and vice versa.

From my re-reading on CTS's function, it likely makes no difference how it's wired (sensor has no polarity, it just increases in resistance as the temperature rises). Correct me if I'm wrong though..!

Otherwise, motor starts and runs great, seems to shift fine too... Although it's near impossible to tell a low speed shift from first to second in the parking lot I'm working in, as this car is so light for it's drive train..! Down shifting from second to first is quite noticeable though. I have a bit more work before I can get it inspected and on the road, 3rd and 4th will have to wait.

Thanks in advance,

Dave

[Six_Shooter]

That is correct the function of the CTS will not be changed with those two wires reversed.